In a manufacturing process of a semiconductor device, like a lamp annealing apparatus or a CVD apparatus, an apparatus which heats and heat-treats substrates, for example, semiconductor wafers by carrying the wafers into a heat-treating furnace one by one, and irradiating the substrates with light is known (for example, Patent Document 1).
FIG. 1 is a schematic sectional view showing the schematic configuration of the conventional lamp annealing apparatus disclosed in Patent Document 1. In this drawing, reference numeral 50 represents a heat-treating furnace, reference numeral 52 represents a light incidence window, reference numeral 54 represents a wafer supporting ring, reference numeral 56 represents a wafer-supporting cylindrical holder, reference numeral 58 represents a lamp housing, reference numeral 60 represents a lamp, reference numeral 62 represents a reflector, and reference numeral 64 represents a shutter plate.
A semiconductor wafer W is carried into the heat-treating furnace 50 through an opening which is not shown, and is horizontally supported on the wafer supporting ring 54. The shutter plate 64 is supported so as to be movable in a horizontal direction by a supporting and moving mechanism which is not shown, and moves between an “actuated position” positioned between the light incidence window 52 and the lamp house 58, and a “retreat position” out of the actuated position. When heat treatment of the wafer W ends and supply of electric power to the lamp 60 stops, the shutter plate 64 moves at high speed from the retreat position to the actuated position, and shields the radiation of heat to the wafer W by the remaining heat immediately after turn-off of the lamp 60 so that the temperature of the wafer W may be rapidly dropped.
The above-mentioned shutter plate 64 is conventionally formed of, for example, a light-weight material, such as aluminum or titanium, so that it can be rapidly moved.    [Patent Document 1]    Japanese Unexamined Patent Application Publication No. 2003-282470 (“HEAT TREATMENT APPARATUS OF SUBSTRATE”)
As described above, an apparatus (for example, rapid heating-cooling type substrate annealing apparatus) in which a heat shield plate is provided between a heater and a workpiece in order to rapidly heat or cool, for example, a glass substrate, etc., and the heat shield plate is moved to give the radiation of the heater to the workpiece or shield the radiation requires high heat resistance and mechanical strength, lightweight properties, etc.
Especially in the thermal resistance, one surface of the heat shield plate faces the heater, and the radiation of the heater radiation does not reach the other surface. Therefore, a large temperature difference may be caused between both the surfaces, and the heat shield plate may be deformed due to the temperature difference.
For example, in a case where a heater is used for rapid heating of a glass substrate, etc., the heater-side temperature becomes a high temperature (for example, around 750° C.) compared with a conventional technique. Therefore, since, for example, the temperature exceeds a melting point of aluminum, it cannot be used.
Further, in this actuated position, the substrate-side temperature is a medium temperature (for example, around 400° C.), and the temperature difference between both surfaces of the heat shield plate reaches about 350° C. or more. Thus, even in a case where titanium, etc. is used, large thermal deformation occurs.
Moreover, even in a case where a carbon material having a high heatproof temperature is used as a structure, the oxidation (burnout) of the carbon material caused by high temperature could not be avoided.
The invention has been invented in order to solve the above-mentioned problems.
That is, the object of the invention is to provide a heat shield plate for a substrate annealing apparatus which is small in thermal deformation, is not oxidized (burnout), is capable of increasing size and reducing weight, even in a case where one surface is exposed to a high temperature (for example, around 750° C.), the other surface is exposed to a temperature significantly lower than the high temperature, and a large temperature difference (for example, about 350° C. or more) is caused between both the surfaces.